The enclosed proposal outlines the multidisciplinary training and research plans for Dr. Tamara Vokes for K23 funding. Dr. Vokes plans an integrated and intensive training program in the area of radiographic texture analysis and its application to osteoporosis research and clinical practice. Training will include courses in medical imaging and image processing which is part of Graduate Programs in Medical Physics offered through the Department of Radiology, and advanced courses in statistics and epidemiology offered through the Department of Health Studies. In addition, training and development will entail intensive mentoring by Dr. Murray Favus and Dr. Maryellen Giger, including weekly meetings, informal discussions and review of manuscripts and grants. Additionally, campus seminars and attendance and presentations at national meetings are integral components of Dr. Vokes' program. With this additional training and mentored research experience, Dr. Vokes will be in a position to develop an independent research program in the area of clinical application of non-invasive assessment of bone structure. The research component of the proposal tests the hypothesis that radiographic texture analysis performed on high-resolution calcaneal images obtained by a portable densitometer can significantly improve the assessment of bone fragility. Currently the only clinical test used for assessment of fragility is bone mineral density (BMD), which assesses bone quantity but not its quality. The latter is believed to be related to trabecular structure or microarchitecture and cannot be easily assessed by currently available modalities. Texture analysis is one of the methods being investigated for non-invasive evaluation of trabecular structure. In Specific Aim 1, it will be determined whether detection of bone fragility in vivo is significantly improved by texture analysis. In Specific Aim 2, it will be determined whether texture analysis changes during 2 years of anti-resorptive therapy and whether it could be used for evaluating therapeutic response. Following the successful completion of the proposed studies, prospective evaluation of texture analysis will be undertaken in larger populations and in different forms of metabolic bone disease.